Due to the significant emission reduction from light and heavy duty vehicles in the past few years, it came out that two-stroke engines are a considerably strong source of pollution in the urban areas where congested traffic made of these vehicles an appropriate alternative to increase mobility. After the entry into force of additional measures on light-duty vehicles (Euro 5/6) and on heavy duty vehicles (Euro VI), the share of two- and three-wheelers in total emissions should increase, in particular they may become higher contributors to gaseous emissions. In this context, the Commission wishes to prepare a recast of the legislation on the type-approval of two- and three-wheelers as well new measures on safety and pollutant emissions to be proposed by mid 2009.
In view of this new legislative process and the preparation of an amendment to the European directives 97/24/EC and 2002/51/EC5 on ¿characteristics of two or three-wheel motor vehicles¿, Transport and Air Quality Unit has worked on the characterization of emissions from motorcycles with the aim of obtaining estimates of the impact of these emission sources on air quality.
In this research program, we have taken into consideration some measures that can be adopted to reduce emissions from the existing mopeds, considering that the next stricter emission standards for mopeds will bring important benefits only in the mid/long-term, when a significant fraction of the fleet will have been replaced by newer vehicles. Indeed, new available after-treatment technologies may reduce emissions from Euro 1, two-Stroke motorcycles by a factor of 10 compared to previous emissions standard. Some of these new technologies for emission reduction are still under development and they are expected to be ready to allow new emission limits in the next legislative proposal.
Another output of this project shows the influence of the engine technology and running conditions on the emissions for regulated pollutants as well as for some non-regulated ones (ie. PM, CO2, PAHs, VOCs, Carbonyls). Throughout the testing programme on mopeds, engine settings and maintenance resulted to affect emissions to a large extent. This means that an inspection and maintenance programme for mopeds can be very effective in reducing emissions. Anti-tampering measures should put in place in order to prevent people from this practice.